I assume you are wanting the 9mm. It appears they only have the 8 round clips for the PPS in 9mm though. Just FYI, those genuine Walther magazines come at premium price, and that is just the way it is.

Places To Try (Both have them in stock)

Shop Shooting Supplies | Reloading | Gunsmithing | Hunting gear — MidwayUSA
Cheaper Than Dirt - America's Ultimate Shooting Sports Discounter

Thanks for your response! Yes, I've checked both of those sites earlier. My local gun store gave me a price of $55/ea so I'll probably just buy them here.

If you can get them at $55 locally and save shipping, that's probably the best you can do. If not here is another option:
Walther PPS Magazine, 9mm, 8 Rnd - Impact Guns